1. Technical Field
The present invention relates to a method and apparatus for displaying at least one three-dimensional (3D) image display area in a two-dimensional (2D) image display area, as well as a method and apparatus for displaying at least one 3D image in a 2D image display area.
2. Discussion of the Related Art
A 3D effect of an object, also called binocular disparity, may be achieved when a viewer or an observer simultaneously views the object through retinas of his or her left and right eyes in different directions and recognizes it by means of the brain. Therefore, to display a 3D image, left and right eyes of a viewer are allowed to view different images using the principle of the binocular disparity, enabling the viewer to recognize the 3D image.
3D display technology may be classified into stereoscopic display technology, which requires a viewer to wear special glasses such as shutter glasses to view a 3D stereoscopic image, and autostereoscopic display technology, which does not require the viewer to wear glasses. A stereoscopic display may use liquid crystal shutter glasses, in which right-eye liquid crystals and left-eye liquid crystals alternately pass and block the light at determined periods, and a driving device for these shutter glasses. Therefore, different left-eye images and right-eye images are separated and provided, allowing the viewer to recognize a relevant stereoscopic image.
Autostereoscopic display technology may include a parallax barrier 3D display device and a lenticular 3D display device. The parallax barrier 3D display device includes a parallax barrier mounted in front of a display panel with pixels arranged in a matrix of rows and columns, and having apertures in the form of a vertical grid. The parallax barrier separates a right-eye image from a left-eye image for the right and left eyes of a viewer, causing binocular disparity between the different right-eye and left-eye images in the display panel. The lenticular 3D display device or a lenticular device includes a lenticular lens sheet having an array of semi-cylindrical lenses in the column direction instead of the parallax barrier in the form of a vertical grid; a flat-surfaced plate facing the lenticular lens sheet; liquid crystal filled between the lenticular lens sheet and the flat-surfaced plate; and electrodes formed on inner sides of the lenticular lens sheet and the flat-surfaced plate. This lenticular device is mounted in front of the display panel, and the display device may switch between 2D and 3D display modes by turning on/off a voltage applied to the electrodes. In the 2D mode, in the viewing direction, the refractive index of the liquid crystal becomes substantially identical to the refractive index of a material used for the lenticular lens sheet depending on the presence/absence of a voltage applied across the liquid crystal material, thereby removing the lens effect of the lenticular device. In this case, the lenticular device may serve as a light transmission plate on the display panel without affecting the path of light coming out from the display panel. On the other hand, in the 3D mode, as the refractive index of the liquid crystal becomes different from the refractive index of the material used for the lenticular lens sheet according to the alignment of the liquid crystal material due to the presence/absence of a voltage applied across the liquid crystal material, the lenticular device may serve as a lens, thereby providing different images to left and right eyes of a viewer and allowing the viewer to perceive a stereoscopic image.
It is important for an autostereoscopic 3D display apparatus to have a number of available view points, because the view point, at which a viewer can watch a 3D image, may be fixed. In order to enable viewers to watch a 3D image at multiple view points, the display apparatus should receive appropriate input data. The appropriate input data may include a sequence of input images for the central view point and a sequence of depth maps corresponding thereto. Pixels may be shifted to depth maps corresponding to input images, generating a set of output images, which correspond to the number of view points. Using the set of output images, an autostereoscopic 3D image signal or a synthesized stereoscopic image signal may be generated to drive a Liquid Crystal Display (LCD) panel using a lenticular device. A look-up table of pixel-shift data based on a plurality of view points and their depth data is stored in a memory, and a display apparatus displays 3D image data by image data shifted based on the pixel-shift data.
If the number of view points increases for 3D image display, a resolution is inversely proportional to the number of view points. When a 3D image is displayed in a 2D image display area, and 2D image displaying is carried out in the 2D image display area in 3D image displaying by the above-described technologies, a resolution of the display for all images including 2D images decreases if the number of view points increases. This decreased resolution negatively impacts display quality.